The present invention relates to an arrangement pertaining to a working implement having the form, for instance, of a fork-frame structure which is provided with one or more, preferably at least two lifting forks or tines, each of which is suspended on a respective lifting frame in a manner which will enable the lifting forks to be moved laterally.
It is known to move forks that are suspended on a fork arm with the aid of hydraulically operated screw-nut devices, for instance of the kind described in WO-A1-88/00894, or with the aid of double-acting hydraulic piston-cylinder devices. These known devices for lateral movement of the lifting forks are highly-complicated, however, and therewith expensive to provide and also require the provision of a hydraulic power source in order to perform their functions.
This type of working implement requires the provision of devices by means of which the working implement can be coupled automatically to the implement attachment means on the working machine, and also with devices by means of which the working implement can be connected to the machine, which includes automatic hose connections for connecting the working implement hydraulically to the hydraulic system of the working machine, so as to enable hydraulically operated functions incorporated in the working implement to be activated directly from the driving cabin of the working machine. These latter types of automatic couplings are also constructed so as to enable a working implement to be coupled to the machine without the driver needing to leave the driver's cabin or to employ the help of an assistant. Despite this, however, it is found that known coupling devices of this kind do not fulfill the aforesaid conditions and are also encumbered with the troublesome drawback that when connecting and disconnecting the quick-couplings of the hydraulic hoses some hydraulic oil is always spilled onto the ground. Although various methods of preventing this have been proposed in the art, none has been successful to any great extent.
Furthermore, when disconnected, such automatic hose couplings are totally exposed and unprotected and therefore subjected to dust, sand, dirt and the like, which, due to the presence of oil on the disconnected quick-connection halves, readily fastens to the couplings and is liable to destroy the hose couplings totally. As a result of this, a parallel problem is one of providing a well functioning automatic coupling device for a working implement which requires access to an energy source of the working machine in order to carry out its function.